Developing through relationships origins of communication, self, and culture

Journal ArticleI began to consider the study of relationships as an intellectual vocation in 1970, the result of two years of college teaching that was part of my work as a United States Peace Corps volunteer in Bogota, Colombia. After another year I began my doctoral training in the Department of Education at the University of Chicago, working on Kenneth Kaye's mother-infant communication studies and struggling to fill the gaps in my knowledge of developmental psychology left by undergraduate and master's degrees in physics and mathematics. I am still struggling, as I believe all professionals struggle, with incompleteness and ambiguity, wavering between conviction and uncertainty. The work that follows is part of an ongoing learning process. Apart from what I have said about these limitations in the body of the text I can also add that it feels finished enough for now, ready for public scrutiny, but open to revision in the future. This book is the product not only of the year over which the writing took place, but also of the past twenty years of my professional development and of my personal life history

2011 Annual Research Symposium Abstract Book

2011 annual volume of abstracts for science research projects conducted by students at Trinity College

2016 Annual Research Symposium Abstract Book

2016 annual volume of abstracts for science research projects conducted by students at Trinity Colleg

Diffusion-weighted and functional magnetic resonance imaging of the brain in preterm and term-born adolescents

Magnetic resonance imaging (MRI) is widely used in clinical and research settings in the adolescent population. Technical development has allowed the use of fine-grained methods to assess both the structural and functional properties of the brain. However, the specific technical limitations and improvements are mostly studied in phantom or adult studies, which may have an impact on their reliability as research tools when studying the younger population. Very preterm (VPT) birth is associated with several neurodevelopmental impairments. The present MRI tools provide opportunities to study brain maturation in detail. This thesis is a part of the multidisciplinary longitudinal follow-up study on the development and functioning of very low birth weight infants from infancy to school age (PIPARI). The follow-up cohort consists of infants born VPT (birth weight ≤1500 g and/or gestational age <32 weeks) in Turku University Hospital in 2001–2006 and term-born controls born in 2001–2004 in the same hospital. This thesis includes only children born VPT in 2004–2006 and controls born between 2003–2004 due to an upgrade of the MRI scanner during the recruitment. In Study I, the diffusion-weighted imaging (DWI) metrics at term-equivalent age were compared to the motor outcome at 11 years of age in children born VPT. Study II assessed the effect of the susceptibility correction to the DWI metrics in a healthy adolescent population. In Study III, temporal fluctuation of the resting state brain functioning was compared between 13-year-old adolescents born VPT and at term. The main prematurity-related findings of this thesis were that the DWI metrics of the corpus callosum, left corona radiata and right optic radiation at term are associated with later motor outcome in children born VPT and that adolescents born VPT show a decrease in active time, fluidity and range in brain activation during rest. These findings may reflect the adjustments in brain microstructure and function caused by the VPT birth. Fine-grained MRI methods are reliable tools for studying the mechanisms behind the clinical phenotypes of adolescents when technical limitations and age-appropriate analysis adjustments are considered.Diffuusiopainotteisen ja toiminnallisen aivojen magneettikuvantamisen käyttö nuoruusiässä entisillä pikkukeskosilla ja täysiaikaisilla verrokeilla Magneettikuvaus (MRI) on laajassa kliinisessä ja tieteellisessä käytössä lapsia ja nuoria tutkittaessa. Tekninen kehitys mahdollistaa yhä hienojakoisempia aivojen tutkimuksia. MRI:n teknisiä korjauksia on tutkittu pääosin mallintamalla tai aikuisilla, mikä voi heikentää luotettavuutta alaikäisillä. Hyvin ennenaikaisesti syntyvillä lapsilla neurologisen kehityksen poikkeavuuksien riski on täysiaikaisena syntyviä suurempi. Poikkeavuudet voivat liittyä aivojen kehityksen muutoksiin, joita nykyisillä tekniikoilla voidaan tutkia aiempaa yksityiskohtaisemmin. Väitöskirja on osa PIPARI-tutkimusta (Pienipainoisten riskilasten käyttäytyminen ja toimintakyky imeväisiästä kouluikään). Seurantakohortti koostuu pikkukeskosina (syntymäpaino ≤1500 g ja/tai raskauden kesto <32 viikkoa) Tyksissä vuosina 2001–2006 syntyneistä lapsista sekä täysiaikaisena 2001–2004 syntyneistä verrokeista. MRI-laitteiston päivityksestä johtuen osatyöt käsittelevät pikkukeskosina vuosina 2004–2006 ja verrokkeina vuosina 2003–2004 syntyneitä. Ensimmäisessä osatyössä verrattiin aivojen diffuusiokuvantamistuloksia entisten pikkukeskosten motoriseen toimintakykyyn 11-vuotiaana. Toinen osatyö käsitteli suskeptibiliteettikorjauksen vaikutusta aivojen diffuusiokuvantamisen mittaustuloksiin. Kolmannessa osatyössä vertailtiin 13-vuotiaiden entisten pikkukeskosten ja verrokkien aivojen aktiivisuuden vaihtelua lepotilassa toiminnallisen MRI-kuvauksen aikana. Tämän väitöskirjan keskosuuteen liittyvät päätulokset olivat lasketun syntymäajan corpus callosumin, vasemman corona radiatan ja oikean optisen radaston diffuusiomittaustulosten yhteys motoriseen kehitykseen 11-vuotiaana sekä pikkukeskosina syntyneillä havaittu aivojen vähäisempi aktiivinen aika ja alentunut aktiivisuuden vaihtelun joustavuus 13-vuotiaana. Nämä löydökset saattavat olla seurausta varhaiseen syntymään liittyvistä aivojen mikrorakenteen ja toiminnan muutoksista. Hienojakoiset MRI-menetelmät vaikuttavat olevan luotettavia nuorisoikäisiä tutkittaessa, kunhan tekniset rajoitteet ja ikäsovitukset huomioidaan

Neural models of inter-cortical networks in the primate visual system for navigation, attention, path perception, and static and kinetic figure-ground perception

Vision provides the primary means by which many animals distinguish foreground objects from their background and coordinate locomotion through complex environments. The present thesis focuses on mechanisms within the visual system that afford figure-ground segregation and self-motion perception. These processes are modeled as emergent outcomes of dynamical interactions among neural populations in several brain areas. This dissertation specifies and simulates how border-ownership signals emerge in cortex, and how the medial superior temporal area (MSTd) represents path of travel and heading, in the presence of independently moving objects (IMOs). Neurons in visual cortex that signal border-ownership, the perception that a border belongs to a figure and not its background, have been identified but the underlying mechanisms have been unclear. A model is presented that demonstrates that inter-areal interactions across model visual areas V1-V2-V4 afford border-ownership signals similar to those reported in electrophysiology for visual displays containing figures defined by luminance contrast. Competition between model neurons with different receptive field sizes is crucial for reconciling the occlusion of one object by another. The model is extended to determine border-ownership when object borders are kinetically-defined, and to detect the location and size of shapes, despite the curvature of their boundary contours. Navigation in the real world requires humans to travel along curved paths. Many perceptual models have been proposed that focus on heading, which specifies the direction of travel along straight paths, but not on path curvature. In primates, MSTd has been implicated in heading perception. A model of V1, medial temporal area (MT), and MSTd is developed herein that demonstrates how MSTd neurons can simultaneously encode path curvature and heading. Human judgments of heading are accurate in rigid environments, but are biased in the presence of IMOs. The model presented here explains the bias through recurrent connectivity in MSTd and avoids the use of differential motion detectors which, although used in existing models to discount the motion of an IMO relative to its background, is not biologically plausible. Reported modulation of the MSTd population due to attention is explained through competitive dynamics between subpopulations responding to bottom-up and top- down signals